As a damping mechanism provided in a hydraulic shock absorber for a vehicle, JP 2006-194335 A, published by the Japan Patent Office in 2006, teaches a damping valve that is provided in an outlet of a port provided in a piston and includes a valve body constituted by a plurality of laminated leaves.
A first oil chamber and a second oil chamber are defined on an inner side of a cylinder of the hydraulic shock absorber by the piston, and a plurality of ports are provided in the piston. A first damping valve is provided in an opening portion of a part of the ports facing the first oil chamber, and a second damping valve is provided in an opening portion of remaining ports facing the second oil chamber.
When the piston displaces in a direction for causing the first oil chamber to contract, working oil in the first oil chamber pushes the second damping valve open and flows into the second oil chamber. When the piston displaces in a direction for causing the second oil chamber to contract, working oil in the second oil chamber pushes the first damping valve open and flows into the first oil chamber.
The first damping valve and second damping valve generate a damping force by applying a flow resistance to the working oil passing therethrough. To ensure that a sufficient damping force is obtained even when an operating speed of the hydraulic shock absorber is low, the leaves constituting the valve body are laminated in an axial direction over a plurality of layers.